Revert "Revert "Disable provider limestone""
Revert "Revert "Disable provider limestone""

This reverts commit 797796ee77dae0a19f24b3cfbb9e9007557c98df.
Connectivity is intermittent, causing AFS timeouts for the
mirror and so breaking builds scheduled there.

Change-Id: I5c682ab59bf570dcd3fd326a28467dc8a9ac7609

openstack-infra/project-config,openstack-infra/project-config